1. Field of the Invention
The present invention relates generally to a biomass composite composition and a foaming method thereof and more particularly, to a biomass composite composition having heat resistance and melt strength suitable for the manufacture of foam product, and a foaming method of the composition.
2. Description of the Related Art
Because plastic causes serious damage to environment, biomass materials are expected to replace petroleum-based plastic as the environment protection consciousness rises. However, it is difficult to produce foam product from biomass materials through traditional foaming method because of its poor heat resistance, such that the application of biomass materials is more limited.
The prior art about manufacturing foam product is enumerated as follows.
1. Taiwan Patent Publication No. 00328545 entitled “Process for the Production of Products of Light Cellular Plastic with Closed Cells” is a process for the production of products of light cellular plastic with closed cells from a plastic composition containing chemical blowing agent and, optionally, other process-regulative substances and additives. Besides, the suitable raw material from which the foam product is made in the prior art is polyurethane, thermoplastic polyamide, epoxy resin or ethylene vinyl acetate (EVA).
2. Taiwan Patent No. I227186 entitled “A Method for Manufacturing Thermoplastic Elastomer Composites under Normal Pressure by a Continuous Foaming Processing” disclosed a method for manufacturing a foam product from a thermoplastic elastomer based composite with the addition of blowing agent and crosslinking agent by a traditional continuous foaming process. Besides, the thermoplastic elastomer used in this method is styrene-butadiene-styrene (SBS), styrene-ethylene/butylene-styrene (SEBS) or styrene-isoprene-styrene (SIS).
3. Taiwan Patent Publication No. 00194501 entitled “Foamed Acrylic Polymer Compositions” disclosed a composition comprising a mixture including 40-90% by weight of a methacrylate ester monomer, 10-60% by weight of polymer, a free radical-producing catalyst, and a foaming agent. Examples of the aforesaid methacrylate ester monomer are methyl methacrylate, ethyl methacrylate, isobutyl methacrylate, n-butyl methacrylate, and the like.
4. Taiwan Patent Publication No. 00400356 entitled “Plastic Blowing Material and Method for Producing the Same” disclosed a method comprising melt blending a styrene-based plastic with a crosslinkable blowing polyolefin and a suitable compatibilizer to thereby produce a styrene-based blowing material. The aforesaid plastic blowing material comprises 50-85 parts of a styrene-based plastic, 15-50 parts of a polyolefin, 10-30 parts of a compatibilizer, 1-10 parts of a blowing agent, 1-2 parts of a crosslinking agent, and 0-2 parts of a blowing promoter and other additives.
5. Taiwan Patent No. I238767 entitled “A Method for Manufacturing Thermoplastic Elastomer Composites having sandwich structure by a Continuous Foaming Processing” disclosed a method for manufacturing a foam product, comprising adding compounding agent, blowing agent, and crosslinking agent into a thermoplastic elastomer based composite, kneading and extruding to form a first sheet, forming a second sheet through the same process, overlying a reinforced sheet and the first sheet on the second sheet to form a sandwich structure, and performing foam process. Besides, the thermoplastic elastomer applied in this method is styrene-butadiene-styrene (SBS), styrene-ethylene/butylene-styrene (SEBS), or styrene-isoprene-styrene (SIS).
As stated above, most of the general raw materials for producing foam products are petroleum-based plastic having superior heat resistance, high melt strength, and high mechanical strength. However, overuse of the petroleum-based plastic leads to waste of resources and is very environmentally unfriendly.
Although a prior biomass composite obtained by blending biomass material and petroleum-based plastic is partially biodegradable, the heat resistance and mechanical strength of the aforesaid biomass composite are inferior, such that it can only be the raw material for plastic injection products or other plastic molding products rather than foamed products. That is, the aforesaid biomass composite cannot be used to produce foamed products such as blades of shutter, heat insulation material, signboard, sound insulation material, ceiling, siding, etc.